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lcd_uni.c
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lcd_uni.c
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/*
** Project: 4-Bit LCD
**
** Author: Steven Pickles
** Date: Friday, April 22, 2005
*
* Mostly rewritten by Stefanie Rausch, July 2014
*
* Changes: - ported from avr to pic
* - Work in single-bit mode, so you can
* use any pins of any ports in any order
* - implemented soft-reset sequence
* - all commands configurable via #define
* - translate()-function to adapt to lcd charset
* - paranoid init-sequence with ready-check
* - now check the busy flag
*/
#include "DevelOS.h"
#ifdef MOD_Display_LCD_Uni
//char position;
const rom char display_driver[7] = "LCDuni\0";
// <editor-fold defaultstate="collapsed" desc="char InitLCD(void)">
char InitLCD(void)
{
char i,cmd,byte,x,y;
LCD.Busy=1;
for(i=0;i<LCDuni_Lines;i++)
{
memset(LCD.Buffer[i], ' ', LCDuni_Cols );
}
// Set all TRIS to Output
TRIS_BL=0;
TRIS_RS=0;
TRIS_RW=0;
TRIS_EN=0;
TRIS_D7=0;
TRIS_D6=0;
TRIS_D5=0;
TRIS_D4=0;
// Set all Portpins to 0 except Backlight
LCD_BL=1;
LCD_D4=0;
LCD_D5=0;
LCD_D6=0;
LCD_D7=0;
LCD_RS=0;
LCD_RW=0;
LCD_EN=0;
/* Init Sequence from Hitachi HD44780U Datasheet
*
* If you need a diffrent sequence, put this one
* in a #ifdef block and wirte your own as #elif
* That way, many Controllers can be supported by
* one source file
*/
// Begin Init Sequence
cmd = 0b00000011; // Reset Command
OS_delay_us(LCD_PON_1); // Power on Delay (40 ms)
writeNibbleToLCD(cmd);
OS_delay_us(LCD_PON_2); // Reset Delay (4.1 ms)
writeNibbleToLCD(cmd);
OS_delay_us(LCD_PON_3); // Init Delay (100 µs)
writeNibbleToLCD(cmd);
cmd = 0b00000010; // Set Interface 4-bit
writeNibbleToLCD(cmd);
// Busy Flag should work now
while(LCD_Busy());
LCD_WriteCMD(LCD_Command[LCD_CMD_fs] | LCD_Setting[2]); // Command: Function set (again, just to be sure the lower nibble arrived)
while(LCD_Busy());
LCD_WriteCMD(LCD_Command[LCD_CMD_dc] | LCD_Setting[1]); // Command: Display Control
while(LCD_Busy()); // wait for LCD
LCD_WriteCMD(LCD_Command[LCD_CMD_clr]); // Command: Clear Display
while(LCD_Busy()); // wait for LCD
LCD_WriteCMD(LCD_Command[LCD_CMD_ems] | LCD_Setting[0]); // Command: Entry Mode Set
/* LCD should be in Ready State Now
* Check this by writing and re-reading a byte to/from DD-Ram.
* Re-Init if no match
* I call this brute-force-init. Just keep trying until success
*/
while(LCD_Busy()); // wait for LCD
LCD_WriteByte('!',0x0); // write a byte
while(LCD_Busy()); // wait for LCD
OS_delay_ns(LCD_E_CYC*2);
byte = LCD_ReadByte(0x0);
if( byte != '!')
{
return 1;
}
else
{
LCD.LineOffset[0] = 0x00;
LCD.LineOffset[1] = 0x40;
LCD.LineOffset[2] = 0x14;
LCD.LineOffset[3] = 0x54;
LCD.Dimensions.height = LCDuni_Lines;
LCD.Dimensions.width = LCDuni_Cols;
LCD.viewy = 0;
LCD.Light = 1;
LCD.Busy = 0;
return 0;
}
}
//</editor-fold>
// <editor-fold defaultstate="collapsed" desc="void RefreshLCD(void)">
void RefreshLCD(void)
{
unsigned char x,y,upperNibble,lowerNibble;
if(LCD.Busy == 1)
{
return;
}
LCD.Busy = 1;
for(y=0;y<LCD.Dimensions.height;y++)
{
unsigned char cmd = LCD_Command[LCD_CMD_sda] | LCD.LineOffset[y];
while(LCD_Busy());
LCD_WriteCMD(cmd); // Set DD-RAM adress
for(x=0;x<LCD.Dimensions.width;x++)
{
upperNibble = LCD.Buffer[y][x] >> 4;
lowerNibble = LCD.Buffer[y][x] & 0x0f;
while(LCD_Busy());
LCD_RS = 1; // Set control bits:
LCD_RW = 0; // RS=1 & RW=0 --> Write to Ram
TRIS_D4= 0;
TRIS_D5= 0;
TRIS_D6= 0;
TRIS_D7= 0;
OS_delay_ns(LCD_T_AS);
writeNibbleToLCD(upperNibble);
OS_delay_ns(LCD_E_CYC);
writeNibbleToLCD(lowerNibble);
OS_delay_ns(LCD_T_AH);
}
}
// for the light, zero should be off, 1 should be max.
// values > 1 will be used for pwm dimming.
if(LCD.Light == 1)
{
LCD_BL=1;
}
else if(LCD.Light == 0)
{
LCD_BL=0;
}
LCD.Busy = 0;
}
//</editor-fold>
// <editor-fold defaultstate="collapsed" desc="char LCD_Busy(void)">
char LCD_Busy(void) // check if LCD is Busy
{
unsigned char byte = 0x00;
unsigned char upperNibble = 0x00;
unsigned char lowerNibble = 0x00;
unsigned char busy = 0x00;
TRIS_D7=1;
TRIS_D6=1;
TRIS_D5=1;
TRIS_D4=1;
LCD_RW = 1; // Set the control bits for read
LCD_RS = 0;
upperNibble = readNibbleFromLCD();
OS_delay_ns(LCD_E_CYC);
// Read the lower nibble
lowerNibble = readNibbleFromLCD();
// Combine the upper and lower nibbles to produce the full 8-bit byte
byte = (upperNibble << 4) | lowerNibble;
busy = byte & 0x80;
if(busy==0x80)
{
OS_delay_ns(LCD_E_CYC);
return 1; // Return TRUE
}
else // Busy bit is low
{
return 0; // Return FALSE
}
}
//</editor-fold>
// <editor-fold defaultstate="collapsed" desc="void LCD_WriteCMD(const unsigned char byte)">
void LCD_WriteCMD(const unsigned char byte)
{
unsigned char byt,upperNibble,lowerNibble;
byt = byte;
upperNibble = byt >> 4;
lowerNibble = byt & 0x0f;
TRIS_D4=0;
TRIS_D5=0;
TRIS_D6=0;
TRIS_D7=0;
LCD_RS = 0; // Set control bits
LCD_RW = 0; // RS=0 & RW=0 --> Command
OS_delay_ns(LCD_T_AS);
writeNibbleToLCD(upperNibble);
OS_delay_ns(LCD_E_CYC);
writeNibbleToLCD(lowerNibble);
OS_delay_ns(LCD_T_AH);
// Done
}
// </editor-fold>
// <editor-fold defaultstate="collapsed" desc="void LCD_WriteByte(const unsigned char byte, const unsigned char adress)">
void LCD_WriteByte(const unsigned char byte, const unsigned char adress) // Write a byte to CG-RAM address
{
char upperNibble = byte >> 4;
char lowerNibble = byte & 0x0f;
unsigned char cmd = LCD_Command[LCD_CMD_sda] | adress;
while(LCD_Busy());
LCD_WriteCMD(cmd); // Set CG-RAM adress
while(LCD_Busy()); // wait for LCD
LCD_RS = 1; // Set control bits:
LCD_RW = 0; // RS=1 & RW=0 --> Write to Ram
TRIS_D4=0;
TRIS_D5=0;
TRIS_D6=0;
TRIS_D7=0;
OS_delay_ns(LCD_T_AS);
writeNibbleToLCD(upperNibble);
OS_delay_ns(LCD_E_CYC);
writeNibbleToLCD(lowerNibble);
OS_delay_ns(LCD_T_AH);
}
//</editor-fold>
// <editor-fold defaultstate="collapsed" desc="void LCD_WriteCGByte(const unsigned char byte, const unsigned char adress)">
void LCD_WriteCGByte(const unsigned char byte, const unsigned char adress) // Write a byte to CG-RAM address
{
char upperNibble = byte >> 4;
char lowerNibble = byte & 0x0f;
LCD_WriteCMD(LCD_Command[LCD_CMD_sca] | adress); // Set CG-RAM adress
while(LCD_Busy()); // wait for LCD
LCD_RS = 1; // Set control bits:
LCD_RW = 0; // RS=1 & RW=0 --> Write to Ram
TRIS_D4=0;
TRIS_D5=0;
TRIS_D6=0;
TRIS_D7=0;
OS_delay_ns(LCD_T_AS);
writeNibbleToLCD(upperNibble);
OS_delay_ns(LCD_E_CYC);
writeNibbleToLCD(lowerNibble);
OS_delay_ns(LCD_T_AH);
}
//</editor-fold>
// <editor-fold defaultstate="collapsed" desc="void LCD_clr(void)">
void LCD_clr(void)
{
char i;
for(i=0;i<20;i++)
{
LCD.Buffer[0][i]=' ';
LCD.Buffer[1][i]=' ';
LCD.Buffer[2][i]=' ';
LCD.Buffer[3][i]=' ';
}
// additionally, send CLR-command to display
while(LCD_Busy()); // wait for LCD
LCD_WriteCMD(LCD_Command[LCD_CMD_clr]); // Command: Clear Display
while(LCD_Busy()); // wait for LCD
}
//</editor-fold>
// <editor-fold defaultstate="collapsed" desc="void writeNibbleToLCD(char nibble)">
/*
** Function: writeNibbleToLCD
** Parameters: selectedRegister - either the command or data register
** that will be written to
** nibble - the four bits to be written to the LCD
** Purpose: Writes a nibble to the LCD.
** Returns: <none>
*/
void writeNibbleToLCD(char nibble)
{
// Output the nibble to the LCD
LCD_EN = 1;
if(nibble & 0x08) LCD_D7=1; else LCD_D7=0;
if(nibble & 0x04) LCD_D6=1; else LCD_D6=0;
if(nibble & 0x02) LCD_D5=1; else LCD_D5=0;
if(nibble & 0x01) LCD_D4=1; else LCD_D4=0;
OS_delay_ns(LCD_E_CYC); // Toggle the enable line to latch the nibble
LCD_EN = 0;
//OS_delay_ns(100);
}
//</editor-fold>
// <editor-fold defaultstate="collapsed" desc="char readNibbleFromLCD()">
/*
** Function: readNibbleFromLCD
** Parameters: selectedRegister - either the command or data register
** that will be read from
** Purpose: Read a nibble from the LCD screen.
** Returns: nibble - the nibble that is read from the LCD
*/
char readNibbleFromLCD()
{
// Create a variable for the nibble
char nibble = 0x00;
LCD_EN = 1;
OS_delay_ns(LCD_E_CYC);
if(LCD_D7==1)
{
nibble++;
}
nibble = nibble << 1;
if(LCD_D6==1)
{
nibble++;
}
nibble = nibble << 1;
if(LCD_D5==1)
{
nibble++;
}
nibble = nibble << 1;
if(LCD_D4==1)
{
nibble++;
}
// Clear the enable
LCD_EN = 0;
//OS_delay_ns(100);
// Finally, return the nibble
return nibble;
}
//</editor-fold>
// <editor-fold defaultstate="collapsed" desc="char LCD_ReadByte(const unsigned char adress)">
/*
** Function: char LCD_ReadByte
** Parameters: const unsigned int adress - adress to read from
** Purpose: Read a byte from the LCD Memory.
** Returns: byte - the byte that is read from the LCD
*/
unsigned char LCD_ReadByte(const unsigned char adress)
{
// Create variables for the lower and upper nibbles as well as the
// entire byte (a combination of the upper/lower nibbles, of course)
char byte = 0x00;
char upperNibble = 0x00;
char lowerNibble = 0x00;
LCD_WriteCMD(LCD_Command[LCD_CMD_sda] | adress); // Set DD-RAM adress
while(LCD_Busy()); // wait for LCD
// Set the data direction for the incoming data
LCD_RW= 1;
LCD_RS= 1;
TRIS_D7=1;
TRIS_D6=1;
TRIS_D5=1;
TRIS_D4=1;
OS_delay_ns(LCD_E_CYC);
upperNibble = readNibbleFromLCD();
OS_delay_ns(LCD_E_CYC);
// Read the lower nibble
lowerNibble = readNibbleFromLCD();
// Combine the upper and lower nibbles to produce the full 8-bit byte
byte = (upperNibble << 4) | lowerNibble;
// Clear the read/write strobe
LCD_RW = 0;
LCD_RS=0;
// Finally, return the byte
return byte;
}
//</editor-fold>
const rom unsigned char LCD_Command[8] = {
0b00000001, // CMD 0 : Clear all Display, reset cursor
0b00000010, // CMD 1 : Return cursor and viewport to 0, leave DDram alone
0b00000100, // CMD 2 : Entry Mode Set
// CMD 2,b0 : Shift Display on write
// CMD 2,b1 : Move Cursor on write
0b00001000, // CMD 3 : Display On/Off/Control
// CMD 3,b0 : Cursor Blink
// CMD 3,b1 : Cursor On/Off
// CMD 3,b2 : Display On/Off
0b00010000, // CMD 4 : Cursor/Display Shift
// CMD 4,b2 : Right/Left
// CMD 4,b3 : Shift/Cursor
0b00100000, // CMD 5 : Function Set
// CMD 5,b2 : Character font
// CMD 5,b3 : Number of Lines
// CMD 5,b4 : 4/8bit Mode
0b01000000, // CMD 6 : Set CG-RAM Address. OR in the address
0b10000000 // CMD 7 : Set DD-RAM Address. OR in the address
};
const rom unsigned char LCD_Setting[3] = {
// Set the right values here, they will be or'ed into the right words, the right time ;)
0b00000010, // CMD 2 : Entry Mode Set
// CMD 2,b0 : Shift Display on write
// CMD 2,b1 : Move Cursor on write
0b00000100, // CMD 3 : Display On/Off/Control
// CMD 3,b0 : Cursor Blink
// CMD 3,b1 : Cursor On/Off
// CMD 3,b2 : Display On/Off
0b00001000, // CMD 5 : Function Set
// CMD 5,b2 : Character font
// CMD 5,b3 : Number of Lines
// CMD 5,b4 : 4/8bit Mode
};
#endif /* MOD_Display_LCD_Uni */